The energy commission estimates that people will save about $18/yr on their electric bills in the first year. According to 2005
census data [DOC WARNING] there are approximately 12million households in CA. Let's assume each household has only 1 TV (probably a low estimate). The lowest PG&E charges me for 1kwh of power is $0.11 (up to 100% of my baseline), the highest is $0.25 (130% or higher of my baseline). Let's assume an average somewhere around $0.16/kwh (that's what my last bill averaged to, anyway).
That means that each year, each household is saving ($18/yr / $0.16/kwh) = 112.5kwh/yr.
Which means that the state of California saves (112.5kwh/house * 12million homes) = 1,350,000,000kwh/yr
Now, let's be realistic. Not everyone's going to run out and buy a new TV year 1, but let's say even 1% of households do. Heck, let's save 0.5% of households do.
1,350,000,000kwh/yr * 0.005 = 6,750,000kwh/yr
Not an insignificant amount of energy by any means.